Web services, such as online advertisers, online marketplaces, online payment providers, social network services or other aggregator websites, may deploy technologies to authenticate users, such as receiving user-typed or browser-provided user information (e.g., identifications and passwords) via login web forms provided by the web services. Once the users are properly authenticated, for example, based on determining that the user-typed or browser-provided user information matches stored user information, then the web services may authorize the users for different services based on their identifications. For example, the web services may provide one user with certain services (e.g., functions) while refraining from providing another user with the same services.